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Periodic Table of Elements

Element Hydrogen – H

Comprehensive data on the chemical element Hydrogen is provided on this page; including scores of properties, element names in many languages, most known nuclides of Hydrogen. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one studies. Using the "Periodic Table of Elements Quick Navigation" graphic at the bottom of the sidebar menu, one can quickly jump from chemical element to chemical element.

Hydrogen Menu

• Hydrogen Page One
  • Overview of Hydrogen
  • Hydrogen's Name in Other Languages
  • Atomic Structure of Hydrogen
  • Chemical Properties of Hydrogen
  • Physical Properties of Hydrogen
  • Regulatory / Health
  • Who/When/Where/How
• Hydrogen Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Hydrogen Page Three
  • Common Chemical Compounds of Hydrogen

Overview of Hydrogen

• Atomic Number:1
• Group: 1
• Period: 1
• Series: Nonmetals

Hydrogen's Name in Other Languages

• Latin: Hydrogenium
• Czech: Vodík
• Croatian: Vodik
• French: Hydrogéne
• German: Wasserstoft - r
• Italian: Idrogeno
• Norwegian: Hydrogen
• Portuguese: Hidrogênio
• Russian:
• Spanish: Hidrógeno
• Swedish: Väte

Atomic Structure of Hydrogen

• Atomic Radius: 0.79Å
• Atomic Volume: 14.4cm³/mol
• Covalent Radius: 0.32Å
• Cross Section (Thermal Neutron Capture)_a/barns: 0.3326
• Crystal Structure: Hexagonal

  

• Electron Configuration:

  1s¹

• Electrons per Energy Level: 1

  Shell Model
  

• Ionic Radius: 0.012Å
• Filling Orbital: 1s¹
• Number of Electrons (with no charge): 1
• Number of Neutrons (most common/stable nuclide): 0
• Number of Protons: 1
• Oxidation States: 1
• Valence Electrons: 1s¹

  Electron Dot Model
  

Chemical Properties of Hydrogen

• Electrochemical Equivalent: 0.037605g/amp-hr
• Electron Work Function:
• Electronegativity: 2.2 (Pauling); 2.2 (Allrod Rochow)
• Heat of Fusion: 0.05868kJ/mol
• Incompatibilities:

  metals, oxidizing materials, metal oxides, combustible materials, halogens, metal salts, halo carbons

• Ionization Potential
  • First: 13.598
• Valence Electron Potential (-eV): 1200

Physical Properties of Hydrogen

• Atomic Mass Average: 1.00794
• Boiling Point: 20.418K -252.732°C -422.918°F
• Coefficient of lineal thermal expansion/K^-1: N/A
• Conductivity

  Electrical:
  Thermal: 0.001815 W/cmK

• Density: 0.0899g/L @ 273K & 1atm
• Description:

  Tasteless, colorless, odorless and extremely flammable gas.

• Enthalpy of Atomization: 217.6 kJ/mole @ 25°C
• Enthalpy of Fusion: 0.059 kJ/mole
• Enthalpy of Vaporization: 0.449 kJ/mole
• Flammablity Class: Highly flammable gas
  • Auto Ignition Temp: 773K 500°C 932°F
    
  • Explosive Limits

    Lower (LEL): 17%
    Upper (UEL): 56%
    

  • Flammable Limits

    Lower (LFL): 4%
    Upper (UFL): 75%
    

  • Flash Point: 20K -253°C -423°F

    Theoretical (there are no oxidizing materials i.e. oxygen in the gas state at this temperature, which is necessary to support combustion.)

• Freezing Point: see melting point
• Heat of Vaporization: 0.44936kJ/mol
• Melting Point: 14.175K -258.975°C -434°F
  
• Molar Volume: 14.1 cm³/mole
• Optical Refractive Index: 1.000132 (gas) 1.12 (liquid)
• Physical State (at 20°C & 1atm): Gas
• Realitive Gas Density (Air=1) = 0.0694
• Specific Heat: 14.304J/gK
• Vapor Pressure = 1570mmHg@-250°C

Regulatory / Health

• CAS Number
  • 1333-74-0 Compressed gas
• UN/NA ID and ERG Guide Number
  • UN1049  / 115 Compressed gas
  • UN1966  / 115 Refrigerated liquid
• RTECS: MW8900000
• NFPA 704
  • Health: 1
  • Fire: 4
  • Reactivity: 0
  • Special Hazard:
• OSHA Permissible Exposure Limit (PEL)
  • No limits set by OSHA
• OSHA PEL Vacated 1989
  • No limits set by OSHA
• NIOSH Recommended Exposure Limit (REL)
  • No limits set by NIOSH
• Levels In Humans:
  Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
  • Blood/mg dm^-3: n/a
  • Bone/p.p.m: n/a
  • Liver/p.p.m: n/a
  • Muscle/p.p.m: n/a
  • Daily Dietary Intake: n/a
  • Total Mass In Avg. 70kg human: n/a

Who / Where / When / How

• Discoverer: Henry Cavendish
• Discovery Location: London England
• Discovery Year: 1766
• Name Origin:

  Greek: hydro (water) and genes (generate)

• Abundance of Hydrogen:
  • Earth's Crust/p.p.m.: N/A
  • Seawater/p.p.m.: N/A
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 73
• Sources of Hydrogen:

  Found chiefly combined with oxygen in the form of water, also found in mines and oil & gas wells. Stars contain a virtually unlimited supply hydrogen and in the universe, hydrogen is the most abundant element (hydrogen makes up 73% of the mass of the visible universe). Annual world production of hydrogen is around 350,000,000,000 cubic meters.

• Uses of Hydrogen:

  Hydrogen's uses include: being used in the production of ammonia, ethanol, hydrogen chloride and hydrogen bromide; the hydrogenation of vegetable oils; hydrocracking, hydroforming and hydrofining of petroleum; atomic-hydrogen welding; instrument-carrying ballons; fuel in rockets; and cryogenic research. Its two heavier isotopes, deuterium (D) and tritium (T), are used respectively for nuclear fission and fusion. Also used in fuel cells for electric cars and other electric machines/devices.

• Additional Notes:

[Last update: 2/22/2007]

Notes below

Hydrogen Menu

• Hydrogen Page One
  • Overview of Hydrogen
  • Hydrogen's Name in Other Languages
  • Atomic Structure of Hydrogen
  • Chemical Properties of Hydrogen
  • Physical Properties of Hydrogen
  • Regulatory / Health
  • Who/When/Where/How
• Hydrogen Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Hydrogen Page Three
  • Common Chemical Compounds of Hydrogen

Related Resources

• Anatomy of the Atom
  Answers many questions regarding the structure of atoms.
• Molarity, Molality and Normality
  Introduces stoichiometry and explains the differences between molarity, molality and normality.
• Molar Mass Calculations and Javascript Calculator
  Molar mass calculations are explained and there is a JavaScript calculator to aid calculations.
• Chemical Database
  This database focuses on the most common chemical compounds used in the home and industry.

Citing this page

If you need to cite this page, you can copy this text:

Kenneth Barbalace. Periodic Table of Elements - Hydrogen – H. EnvironmentalChemistry.com. 1995 - 2008. Accessed on-line: 7/6/2008
http://EnvironmentalChemistry.com/yogi/periodic/H.html
.